Active head restraint with self resetting mechanism

ABSTRACT

An apparatus includes a seat back having an outer surface that selectively contacts a seat occupant and a head restraint extending from the seat back that has a head restraint portion that selectively contacts the seat occupant. The head restraint portion is moveable between a forward position and a rearward position. The apparatus also includes a head restraint control assembly having an actuator, a lock mechanism, and a lock mechanism resetting device. The actuator transfers an actuation force to the head restraint portion for initiating movement of the head restraint portion from the rearward position to the forward position. The lock mechanism selectively restrains the headrest portion from moving from the forward position to the rearward position. The lock mechanism will restrain the headrest portion from moving from the forward position to the rearward position in a first actuation event and selectively reset by action of the lock mechanism resetting device in order to restrain the headrest portion from moving from the forward position to the rearward position in a second actuation event. The lock mechanism resetting device will reset the lock mechanism without manipulation from an outside source.

TECHNICAL FIELD

The disclosure generally relates to head restraint assemblies invehicles.

BACKGROUND

A vehicle typically includes a head restraint for each seat. These headrestraints generally extend vertically from the seat back and mayprevent neck hyperextension. Typical sensor actuated head restraints mayhave mechanisms for moving the head restraint forward during a crashthat include a source of stored energy and a trigger. The source ofstored energy may be a compressed spring or source of pyrotechnic(chemical) or electrical energy that is used to move the headrest to adesired position. The trigger may be a latch or electrical activationdevice that initiates the movement of the headrest. However, thesesystems rely on complexity and may provide additional failure modes forthe systems.

Some head restraints are intended to move forward during a crash, butmay return to a rearward position when a delay in remaining in theforward position could be desirable. What is needed, therefore, is acontrol system for a head restraint control system that may delay thereturn of a head restraint to the rearward position.

SUMMARY

An illustrative embodiment includes a seat back having an outer surfacethat selectively contacts a seat occupant and a head restraint extendingfrom the seat back that has a head restraint portion that selectivelycontacts the seat occupant. The head restraint portion is moveablebetween a forward position and a rearward position. The apparatus alsoincludes a head restraint control assembly having an actuator, a lockmechanism, and a lock mechanism resetting device. The actuator transfersan actuation force to the head restraint portion for initiating movementof the head restraint portion from the rearward position to the forwardposition. The lock mechanism selectively restrains the headrest portionfrom moving from the forward position to the rearward position. The lockmechanism will restrain the headrest portion from moving from theforward position to the rearward position in a first actuation event andselectively reset by action of the lock mechanism resetting device inorder to restrain the headrest portion from moving from the forwardposition to the rearward position in a second actuation event. The lockmechanism resetting device will reset the lock mechanism withoutmanipulation from an outside source.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, preferred illustrative embodiments areshown in detail. Although the drawings represent some embodiments, thedrawings are not necessarily to scale and certain features may beexaggerated, removed, or partially sectioned to better illustrate andexplain the present invention. Further, the embodiments set forth hereinare not intended to be exhaustive or otherwise limit or restrict theclaims to the precise forms and configurations shown in the drawings anddisclosed in the following detailed description.

FIG. 1 is a front view of a portion of an active head restraint systemaccording to an embodiment.

FIG. 2 is a side view of a portion of the system of FIG. 1, illustratedin a first configuration.

FIG. 3 is a side view of a portion of the system of FIG. 1, illustratedin a second configuration, with the illustration of FIG. 2 overlaid inphantom for comparison.

FIG. 4 is a front view of a portion of a head restraint system accordingto another embodiment.

FIG. 5 is a side view of a portion of the system of FIG. 4, illustratedin a first configuration.

FIG. 6 is a side view of a portion of the system of FIG. 4, illustratedin a second configuration.

FIG. 7 is side schematic view of a lock mechanism and lock mechanismresetting device, according to an embodiment, illustrated in a firstconfiguration.

FIG. 8 is a side schematic view of the lock mechanism of FIG. 7,illustrated in a second configuration.

FIG. 9 is an enlarged view of portion 9 of FIG. 7.

FIG. 10 is an enlarged view of portion 10 of FIG. 8.

FIG. 11 is side schematic view of a lock mechanism, according to anembodiment, illustrated in a first configuration.

FIG. 12 is a side schematic view of the lock mechanism of FIG. 11,illustrated in a second configuration.

FIG. 13 is an enlarged view of portion 13 of FIG. 11.

FIG. 14 is an enlarged view of portion 14 of FIG. 12.

FIG. 15 is a perspective view of a head restraint system according to afurther embodiment, illustrated in a first configuration.

FIG. 16 is a perspective view of a head restraint system of FIG. 15,illustrated in a second configuration.

FIG. 17 is a lock mechanism according to a further embodiment.

FIG. 18 is a phantom view of the mechanism of FIG. 17.

FIG. 19 is side schematic view of a lock mechanism, according to anembodiment, illustrated in a first configuration.

FIG. 20 is a side schematic view of the lock mechanism of FIG. 19,illustrated in a second configuration.

DETAILED DESCRIPTION

FIGS. 1-3 illustrate an active head restraint system 20. System 20includes a seat back 22, a head restraint 24, and a head restraintcontrol system 26. The seat back 22 includes a seat back frame 30attached to a seat bottom (not shown), and a seat back outer covering(not shown). The seat back frame 30 includes horizontal member 40, afirst vertical member 42, a second vertical member 44, a head restraintattachment portion 46, and a deceleration device attachment portion 48.The head restraint 24 includes a structural portion 50, a first link 52,a second link 54, and a head restraint outer covering 56.

The head restraint control system 26 includes a thorax member, or thoraxback plate, 60, a first plate link 62, a second plate link 64, aninterconnecting member 66 having an axis A-A, a rotary damper, ordeceleration device 68, and a latch, or lock mechanism 70. In theembodiment illustrated, the head restraint control system 26 ispositioned within the seat back outer covering of the seat back 22. Asbest seen in FIG. 1, the first plate link 62 is attached to the firstvertical member 42, and the second plate link 64 is attached to thesecond vertical member 44 to form a head restraint assembly 74 thatincludes the head restraint 24 the thorax plate 60, structural portion50, first link 52, second link 54, first plate link 62, second platelink 64, and interconnecting member 66.

As best seen in FIGS. 2 and 3, the interconnecting member 66 isrotatably attached to the seat back frame 30 at about the axis A-A.Specifically, the horizontal member 40 of the seat back frame 30includes a horizontal attachment member 80, a first vertical attachmentmember 82, and a second vertical attachment member 84. As illustrated,the horizontal attachment member 80 includes a first end 90 and a secondend 92 and is positioned below the remainder of the horizontal member40. The first vertical attachment member 82 extends between the firstend 90 and horizontal member 40. The second vertical attachment member84 extends between the second end 92 and the horizontal member 40. Boththe first vertical attachment member 82 and the second verticalattachment member 84 include a pivotal attachment 96 formed therein. Inthe embodiment illustrated, the interconnecting member 66 is acylindrical rod that is interposed through the pivotal attachments 96for relative rotation therebetween about the axis A-A. Theinterconnecting member 66 is a torsion rod that biasingly urges the headrestraint assembly 74 toward the rearward position, although othersprings or biasing means may be interconnected between the headrestraint assembly 74 and the seat back frame 30 for the same purpose.

Therefore, the head restraint assembly 74 is rotatable generally aboutthe axis of the interconnecting member 66 from a first configuration, orrearward position, of FIG. 2 to a second configuration, or forwardposition, of FIG. 3. When a seat occupant is properly positioned withinthe seat bottom and the seat back 22, the seat occupant's head may behorizontally positioned relative to the head restraint 24, and the seatoccupant's thorax may be horizontally positioned relative to the thoraxplate 60. In another potential embodiment not illustrated, therotational axis A-A may be moved forward (in the direction of the arrowF) while other components remain in about the same position to permitthe head restraint 24 to move upward as the head restraint rotatesforward, as desired.

The rotary damper 68 may provide some resistance to rotation of the headrestraint assembly 74 toward the forward position, and will providesignificantly greater resistance to rotation of the head restraintassembly 74 toward the rearward position. In this manner, the rotarydamper 68 may provide some amount of time delay for the head restraintassembly 74 to return to the rearward position (first configuration) andmay reduce the initial jolt imparted to the lock mechanism 70 as thelock mechanism 70 engages to retain the head restraint assembly 74 inabout the forward position.

FIGS. 4-6 illustrate another embodiment of a head restraint system assystem 120. System 120 includes a seat back 122, a head restraint 124,and a head restraint control system 126. The seat back 122 includes aseat back flame 130 attached to a seat bottom (not shown), and a seatback outer covering (not shown). The seat back frame 130 includeshorizontal member 140, a first vertical member 142, a second verticalmember 144, a head restraint attachment portion 146, and a decelerationdevice attachment portion 148. The head restraint 124 includes astructural portion 150, a first link 152, a second link 154, a headrestraint outer covering 156, and a guide mechanism 158.

The head restraint control system 126 includes a thorax member, orthorax back plate, 160, a first plate link 162, a second plate link 164,an interconnecting member 166 having an axis B-B, a damper, ordeceleration device 168, and a latch, or lock mechanism 170. In theembodiment illustrated, the head restraint control system 126 ispositioned within the seat back outer covering of the seat back 122.

The system 120 further includes a head restraint assembly 174. The headrestraint assembly 174 includes the head restraint 124, the thorax plate160, a rack and pinion device 178, and a moveable head restraint portion180. The rack and pinion device 178 includes a pinion 182 affixed to theinterconnecting member 166 and rotatable about the axis B-B, and a rack184 meshed with the pinion 182 such that rotational movement of thepinion 182 will cause linear movement of the rack 184 generally in thedirection of arrows F or R (between a rearward position of FIG. 5 and aforward position of FIG. 6). The guide mechanism 158 includes a pair ofstabilizers 190 that are attached to the seat back frame 130, and atelescopic guide 192 (FIG. 6) that guides the moveable head restraintportion 180 for linear movement generally in the direction of arrows For R. As illustrated in a comparison of FIGS. 5 and 6, the moveable headrestraint portion 180 will move generally in the direction of arrows For R relative to the seat back portion 130 as the telescopic guide 192restrains movement of the moveable head restraint portion 180 in otherdirections. The moveable head restraint portion 180 includes the outercovering 156 and is attached to the rack 184 such that linear movementof the rack 184 generally in the direction of arrows F or R will resultin linear movement of the head restraint portion 180 generally in thedirection of arrows F or R, as best illustrated in a comparison of FIGS.5 and 6.

As best seen in FIGS. 1-6, the head restraints 24) 124 may include afilling (not numbered) that absorbs some energy during an event wherethe seat occupant impacts the head restraint 24, 124. This filling maybe any suitable foam, or other suitable materials that will decelerate aseat occupant's head.

FIGS. 7-10 illustrate additional components of the active head restraintcontrol system 26. The head restraint control system 26 also includes alatch 200, and a lock mechanism resetting device 202. The latch 200includes a latch arm 210 that extends from the thorax plate 60 tosupport a latching portion 212. The latching portion 212 includes agenerally vertical surface 214, as discussed in greater detail below. Asschematically illustrated, the latching portion 212 extends from thehead restraint assembly 74. In the embodiment illustrated, the headrestraint assembly 74 also includes an actuation arm 216 extendingtherefrom. The actuation arm 216 includes a generally vertical surface218.

The lock mechanism resetting device 202 includes a reset cylinder 220having an actuation piston assembly 222, a reaction piston assembly 224,an orifice membrane 226, an orifice obstruction 228, and a reactionspring 230 at least partially interposed therein. The lock mechanismresetting device 202 also includes a linear force transmitter 240 havinga cam assembly 242 fixed for rotation relative to the reset cylinder220, and a slide 246. The cam assembly 242 is fixed for rotationrelative to the seat back frame 30, and the slide 246 is secured forcontrolled, guided movement in the forward direction F and the rearwarddirection R relative to the seat back frame 30. A flexible cable 248interconnects the actuation arm 216 and the slide 246, as discussed ingreater detail below.

The reset cylinder 220 is at least partially defined by a top end 250, abottom end 252, a cylindrical inside surface 254, a top wall 256, and abottom wall 258. The top end 250 has a top opening 260, and the bottomend 252 has a bottom opening 262 formed therein. The reset cylinder 220may be sealed with only the top opening 260 and the bottom opening 262providing an escape path for air. The actuation piston assembly 222includes a generally cylindrical actuation body 270 having an actuationmember 272 extending therefrom. The actuation body 270 is defined by anouter cylindrical surface 274, an actuation force surface 276, and anopposing surface 278. The reaction piston assembly 224 includes agenerally cylindrical reaction body 280 having a reaction member 282extending therefrom. The reaction body 280 is defined by an outercylindrical surface 284, a reaction force surface 286, and an opposingsurface 288.

As illustrated, the interior volume of the actuation cylinder issegregated into a top volume 290 and bottom volume 292. The top volume290 is located between the top end 250 and the orifice membrane 226, andthe bottom volume 292 is located between the bottom end 252 and theorifice membrane 226. The reset cylinder 220 is further segregated intovariable volumes, such as an actuation volume 294 which is locatedbetween the actuation force surface 276 and the orifice membrane 226,and a reaction volume 296, which is located between the reaction forcesurface 286 and the orifice membrane 226.

The actuation member 272 is interposed through the bottom opening 262,and the reaction member 282 is interposed through the top opening 260.The orifice membrane 226 includes a slightly frusto-conical body 298,having a circular central inlet orifice 306 and at least one outletorifice 308 formed therein. The body 298 is secured about an outercircumference CB to the inside surface 254. The reaction spring 230 iscoiled around the reaction member 282 and the orifice obstruction 228 isinterposed between the body 298 and the reaction piston assembly 224. Asillustrated, the orifice obstruction 228 is a ball that is larger indiameter than the inlet orifice 306.

The outer cylindrical surface 274 of the actuation body 270 is sealedwith the inside surface 254 of the reset cylinder 220, and the outercylindrical surface 284 of the reaction body 280 may be sealed with theinside surface 254 of the reset cylinder 220 such that both theactuation piston assembly 222 and the reaction piston assembly 224 arereadily slidable along the axis of the reset cylinder 220 and relativeto the reset cylinder 220.

The cam assembly 242 rotates about a cam axis, shown at CA, and includesa cam body 340 having a cammed surface 342 and a guide rod 344 extendingtherefrom. The slide 246 has a slide body 348 having a slide groove 350formed therein. The cam body 340 is positioned such that the cammedsurface 342, upon rotation of the cam body 340, will contact and guidethe actuation member 272 up, generally in the direction of the arrow U.The guide rod 344 is interposed within the slide groove 350 such thattranslation of the slide 246 generally in the direction of arrow R willrotate the cam body 340. As best seen in a comparison between FIGS. 9and 10, when the slide 246 moves in the direction of arrow R, the cambody 340 will rotate causing the actuation piston assembly 222 to movein the direction of arrow U.

Movement of the actuation piston assembly 222 in the direction of arrowU will compress the fluid (not numbered) within the actuation volume294. This compressed fluid will lift the orifice obstruction 228 andpermit the compressed fluid to escape into the reaction volume 296. Oncein the reaction volume 296, the compressed fluid will lift the reactionpiston assembly 224 in the direction of arrow U, causing the reactionmember 282 to extend from the top opening 260, as best seen in FIG. 10.

In operation, and assuming an event such as a rear-end collision thatwould accelerate the seat back 22 forward relative to a seat occupant,the kinetic energy generated by the reactive force between therelatively stationary seat occupant and the seat back 22 movinggenerally in the direction F, will result in a force on the thorax plate60 generally in the direction of arrow R. This force on the thorax plate60 will move the thorax plate 60 generally in the direction of arrow Ras the head restraint assembly 74 rotates about the axis A-A to move thehead restraint 24 generally in the forward direction (in the directionof arrow F) to permit the head restraint 24 to move toward the seatoccupant's head.

As the thorax plate 60 moves generally in the direction of arrow R, thesurface 218 of the actuation arm 216 contacts the slide 246, causing theslide 246 to move generally in the direction of arrow R. As the slide246 moves generally in the direction of arrow R, the reaction member 282is extended from the reset cylinder 220, as discussed above andillustrated in FIG. 10. The reaction member 282 will interfere with thesurface 214 of the latching portion 212 to restrain the head restraintassembly 74 in the forward position illustrated in FIGS. 3 and 8. Thusactuated in a first actuation event, the head restraint assembly 74 willremain in the forward position until the lock mechanism 70 is unlatched.

As best seen in FIG. 10, the latch 200 engages the first plate link 62as the thorax plate 60 moves rearwardly (in the direction of arrow R) torestrain the thorax plate 60 in a rearward, locked position and the headrestraint 24 in a forward, locked position (FIGS. 8 and 10).Collectively, the latch 200 and the reaction member 282 cooperate toform the lock mechanism 70. Compressed fluid generally refers to a fluidwith a pressure greater than atmospheric.

To continue discussing the operation of the head restraint controlsystem 26, the unlatching of the lock mechanism 70 and the resetting ofthe head restraint control system 26 will now be presented. Once thehead restraint control system 26 has actuated and the head restraintassembly 74 is latched in the forward position of FIG. 3 by the lockmechanism 70, the actuation piston assembly 222 has stopped and is nolonger compressing the fluid. When the load releases on the thorax plate60, the orifice obstruction 228 will seat with the inlet orifice 306 toseal the inlet orifice 306. The fluid contained within the reactionvolume 296 will be compressed by the spring 230 exerting a force throughthe reaction surface 286. The compressed fluid contained within thereaction volume 296 will then be released through orifice 308, therebypermitting the reaction piston assembly 224 to move in the direction ofthe arrow D. As the reaction piston assembly 224 continues to move inthe direction of the arrow D, the interference between the reactionmember 282 and the surface 214 will cease as the reaction member 282translates below the surface 214, thereby unlatching the head restraintassembly 74. The head restraint assembly 74 will then rotate from theforward position of FIG. 3 to the rearward position of FIG. 2.

As best seen in FIG. 10, the actuation piston assembly 222 may not besealed tightly with the inside surface 254, thereby permitting an escapeof compressed fluid therebetween to allow the reaction piston assembly224 to move in the direction of arrow D as the fluid that escapesthrough orifice 308 escapes between the actuation piston assembly 222and the inside surface 254. Also, when the head restraint assembly 74returns to the first configuration, or rearward position of FIG. 2 fromthe forward position of FIG. 3, the actuation arm urges the slide 246 inthe direction of the arrow F through the cable 248.

Thus reset, the head restraint assembly 74 is in the first configurationand capable of being re-actuated and reset, as described herein. Thatis, the head restraint system 20 will actuate in a first actuationevent, automatically reset without any outside source, and actuate in asecond actuation event, thereby providing a self-resetting function forthe head restraint assembly 74 after being latched during the firstactuation event. As illustrated, the outlet orifice 308 is sized so asto provide a controlled, predetermined amount of time for unlatching thelock mechanism 70. In the embodiment illustrated, the lock mechanismresetting device 202 will unlatch the lock mechanism 70 in a range oftime between about 1.0 second to about 5 seconds. Since an actuationevent may generally take place in about less than 300 milliseconds (ms),a lower desired value for the predetermined time would be greater than300 ms.

To summarize the operation of the embodiment illustrated as system 20, afirst actuation event occurs where at least one of the seat occupant andthe seat back experience a change in velocity, and the seat back movesrelatively toward the seat occupant. This relative movement develops arearward force on the thorax plate 60, moving the thorax plate 60generally in the direction of arrow R relative to the seat back frame30. The force exerted on the head restraint assembly 74 generates anamount of kinetic energy that is transmitted to the system 20. Thisrelative movement of the thorax plate 60 and the seat back frame 30 willcause the head restraint assembly 74 to rotate about the axis A-A as thehead restraint 24 moves relative to the seat back frame 30 in thegeneral direction of arrow F. The head restraint assembly 74 will thenbe restrained in the forward position by the lock mechanism 70. At leasta portion of the kinetic energy, referred to as the actuation energy, isexpended in rotating the head restraint assembly 74. At least a portionof the kinetic energy, referred to as the resetting energy, is expendedin urging the slide 246 in the direction of the arrow R. At least aportion of the resetting energy is then mechanically transferred, orconverted, to the reaction spring 230. The reaction spring 230 thenurges the reaction member 282 to disengage with latching portion 212after a finite amount of time to unlatch the lock mechanism 70.

FIGS. 11-18 illustrate alternative embodiments of the lock mechanism 70that also may unlatch by use of a lock mechanism resetting device aftera desired amount of time after actuation of a lock mechanism. Theseembodiments use a clockwork mechanism to effect a time delay forunlatching a lock mechanism for a head restraint system, such as systems20, 120.

FIGS. 11-14 illustrate a lock mechanism 170. The lock mechanism 170includes a latch 300, and a lock mechanism resetting device 302. Thelatch 300 includes a reset arm 310 that extends from the thorax plate160 and a latching portion 312 that is pivotally attached to the seatback frame 130. The latching portion 312 includes a generally verticalsurface 314, a latching arm 316, and a latch spring 318, as discussed ingreater detail below. As schematically illustrated, the reset arm 310extends from the head restraint assembly 174. In the embodimentillustrated, the lock mechanism resetting device 302 also includes agear reduction device 320, a spring 322, a gear 328, a rack 330, and acable 332. The gear reduction device 320 includes a reset actuator 334operatively attached to the spring 322, and a time delay mechanism 336,such as is disclosed in U.S. Pat. Nos. 1,867,001; 4,062,210 and4,359,883.

The spring 322 is compressed as the thorax plate 160 moves in thedirection of the arrow R as the reset arm 310 biases at least a portionof the spring 322 in the direction of the arrow R. The cable 332operably connects a portion of the time delay mechanism 336 with thelatching portion 312 such that a portion of the time delay mechanism 336will pull the cable 332 to unlatch the lock mechanism 170.

As the thorax plate 160 and the reset arm 310 move in the direction ofthe arrow R, the reset arm 310 engages the latching portion 312 suchthat the surface 314 will interfere with the reset arm 310 to restrainthe head restraint assembly 174 in the forward position as seen in FIG.12. As illustrated, the latch spring 318 will retain the surface 314 inthe interference with the reset arm 310.

In the embodiment illustrated, the reset arm engages the latchingportion 312 and compresses the spring 322. When the spring 322 iscompressed, a reset energy is stored in spring 322. This reset energy isthen used to drive the time delay mechanism 336 as the cable 332 ispulled to pull the latching portion 312 such that the surface 314 willnot interfere with the reset arm, thereby unlatching the lock mechanism170 and permitting the head restraint assembly 174 to move toward therearward position as seen in FIG. 11. Thus configured, the lockmechanism resetting device 302 will unlatch the lock mechanism 170 aftera desired amount of time preceding the actuation of the system 120.

FIGS. 15-18 illustrate a portion of a head restraint control system 326including a lock mechanism 370 and a head restraint assembly 374.Similar to the head restraint assembly 74, the head restraint assembly374 includes a head restraint 324, a thorax plate 360, a structuralportion 350, a first link 352, a second link 354, a first plate link362, a second plate link 364, and a pair of interconnecting members 366.The lock mechanism 370 includes a latch 400 extending from a lockmechanism resetting device 402. The interconnecting members 366pivotally interconnect the head restraint assembly 374 to a seat backframe (not shown) thereby allowing the head restraint assembly 374 topivot about an axis C-C from a rearward position (illustrated in phantomin FIG. 15) to a forward position (FIG. 15). In the embodimentillustrated, the interconnecting members 366 are torsional members thatbias the head restraint assembly 374 in the rearward position, althoughother biasing devices may be used to urge the head restraint assembly374 toward the rearward position.

The latch 400 includes a generally planar latch end surface 420 and agenerally cylindrical latch surface 422. The latch 400 extends from thelock mechanism 370 and toward the head restraint assembly 374 such thateach latch end surface 420 of one lock mechanism 370 will contact one ofthe first plate link 362 and the second plate link 364, as bestillustrated in FIG. 16.

The lock mechanism resetting device 402 includes a milled reset body 430having a front surface 432, an inboard surface 434, an outboard surface436, and a back surface 438. The body 430 has a latch bore 442, a resetslot 444, an interference ball bore 446 formed therein, a cam biasingbore 448, and an interference block 450 extending therefrom. The latchbore 442 is a generally cylindrical bore that extends from the inboardsurface 434 of the body 430 (while not intersecting the outboard surface436) parallel to the reset slot 444 which is formed in the front surface432 and extends from the front surface 432 to the latch bore 442. Theinterference ball bore 446 is a generally cylindrical bore that extendsfrom the front surface 432 at the interference block 450 to the latchbore 442. The interference block 450 has a block bore 452 formed thereinand an interference pin 454 extending therefrom. A cam pin 456 extendsthrough the cam biasing bore 448 and is rotatable relative to the body430.

The lock mechanism resetting device 402 also includes an interferenceball 458 positioned within the interference ball bore 446, a reset cam460 attached to a first end 462 of the cam pin 456, a reset bolt 464attached to the latch 400 and extending through the reset slot 444, anda cam biasing mechanism 466 attached to a second end 468 of the cam pin456. The reset cam 460 has a generally cylindrical outer surface 472with a cam lobe 474 extending therefrom. Further, the lock mechanismresetting device 402 includes a latch spring 480 positioned within thelatch bore 442 to bias the latch 400 away from the outboard surface 436.The cam biasing mechanism 466 may be a spring that is attached to theback surface 438 and wound to ensure that the reset cam 460 will rotateseveral revolutions, as discussed in greater detail below. Theinterference pin 454, when extended from the block bore 452, willinterfere with the reset cam 460 to prevent rotation of the reset cam460. When the interference pin 454 is not extended from the block bore452, the reset cam 460 will rotate clockwise, as viewed in FIG. 18.

The interference ball 458 is moveable in the interference ball bore 446from a forward interference position (closer to the front surface 432)to a non-interference position (closer to the back surface 438). In theinterference position, the interference ball 458 will urge theinterference pin 454 to extend from the block bore 452 to inhibitrotation of the reset cam 460. In the non-interference position, theinterference ball 458 will permit the interference pin 454 to retractinto the block bore 452 and permit the reset cam 460 to rotate.

The latch 400 is moveable in the latch bore 442 from an unlatchedposition (closer to the outboard surface 436) to a latched position(further from the outboard surface 436). In the unlatched position, theinterference ball 458 is urged toward the interference position, and theinterference ball 458 will urge the interference pin 454 to extend fromthe block bore 452 to inhibit rotation of the reset cam 460. In thelatched position, the interference ball 458 is permitted to move to thenon-interference position, where the interference ball 458 will permitthe interference pin 454 to retract into the block bore 452 and permitthe reset cam 460 to rotate.

As the reset cam 460 rotates in the clockwise direction, the cam lobe474 will contact the reset bolt 464 (which is attached to the latch 400)and urge the reset bolt 464 and the latch 400 toward the outboardsurface 436, Once the reset cam 460 urges the reset bolt 464 and thelatch 400 into the unlatched position, the latch 400 urges theinterference ball 458 into the interference position where theinterference pin 454 inhibits further rotation of the reset cam 460.Also, when the latches 400 are in their respective unlatched positions(after a first actuation event), the head restraint assembly 374 willrotate toward the rearward position, thereby resetting the headrestraint assembly 374 for a second actuation event.

In operation, and assuming an event such as a rear-end collision thatwould accelerate the seat back (not shown) forward relative to a seatoccupant, the kinetic energy generated by the reactive force between therelatively stationary seat occupant and the seat back moving generallyin the direction F, will result in a force on the thorax plate 360 (FIG.15) generally in the direction of arrow R. This force on the thoraxplate 360 will move the thorax plate 360 generally in the direction ofarrow R as the head restraint assembly 374 rotates about the axis C-C tomove the head restraint 324 generally in the forward direction (in thedirection of arrow F) to permit the head restraint 324 to move towardthe seat occupant's head.

As the thorax plate 360 moves generally in the direction of arrow Rtoward the rearward position, the first plate link 362 and the secondplate link 364 will move generally in the direction of arrow R. As thefirst plate link 362 and the second plate link 364 move generally in thedirection of arrow R, the first plate link 362 and the second plate link364 will pass beyond contact with the latch end surfaces 420, and thelatch 400 of each lock mechanism 370 will extend from the lock mechanism370, as discussed above, thereby restraining the head restraint assembly374 in the forward position illustrated in FIG. 15. Thus actuated in afirst actuation event, the head restraint assembly 374 will remain inthe forward position until the lock mechanism 370 is unlatched, also asdiscussed above.

As best seen in FIG. 15, each latch 400 engages one of the first platelink 362 and the second plate link 364 as the thorax plate 360 movesrearwardly (in the direction of arrow R) to restrain the thorax plate360 in a locked position and the head restraint 324 in a forward, lockedposition.

In the embodiments illustrated, lock mechanisms 70, 170, 370 include atime delay resetting feature for automatic reset of the lock mechanismas the head restraint is returned to the rearward position. That is, thelock mechanisms presented herein are unlocked after a desired amount oftime following an activation of the head restraint toward the forward,locked position of FIGS. 3 and 6. Also, the lock mechanisms 70, 370 havean integral lock mechanism resetting device 202, 402 that work inconjunction with the latch 200, 400, while the lock mechanism 170 has alatch 300 that may or may not operate with a lock mechanism resettingdevice, such as the lock mechanism resetting device 302.

FIGS. 19-20 schematically illustrate yet another embodiment of an activehead restraint system, as an active head restraint system 520. System520 includes a seat back 522, a head restraint 524, and a head restraintcontrol system 526. The seat back 522 includes a seat back frame 530attached to a seat bottom (not shown), and a seat back outer covering(not shown). The seat back frame 530 includes an upper horizontal member540, a first vertical member 542, a second vertical member 544, andahead restraint attachment portion 546.

The head restraint control system 526 includes a thorax member, orthorax back plate, 560, a first plate member 562, a second plate link564, an interconnecting member 566 having an axis A-A, and a latch, orlock mechanism 570. In the embodiment illustrated, the head restraintcontrol system 526 is positioned within the seat back outer covering ofthe seat back 522. The thorax back plate 560 will rotate about an axis Grelative to the second plate link 564, as discussed in greater detailbelow.

As best seen in FIGS. 19 and 20, the first plate member 562 is rotatablyattached to the horizontal member 540 generally about the axis A-A atthe interconnecting member 566. The first plate member 562 is rigidlyattached to the second plate link 564. The first plate member 562supports the head restraint 524 at the head restraint attachment portion546.

A head restraint assembly 574 is at least partially illustrated andincludes the head restraint 524, the thorax plate 560, the first platemember 562, the second plate link 564, and the interconnecting member566. The thorax plate 560 includes a first plate member 580, anactuating member 582, and may also include a bracing member 584 toretain the first plate member 580 in a desired orientation relative tothe second actuating member 582.

In the embodiment illustrated, the first plate member 562 is a hollowcylindrical tube that includes a guide pin 590 at least partiallyinterposed therein, a graphite washer 592 interposed between the guidepin 590 and the first plate member 562, and a first plate member spring596 biasing the guide pin 592 toward the actuating member 582. The firstplate member spring 596 biasing the guide pin 590 toward the actuatingmember 582 with a force that is sufficient to overcome the resistance tomovement provided by the graphite washer 592.

Additionally, the head restraint assembly 574 may include a torsion rodthat biasingly urges the head restraint assembly 574 toward the headrestraint rearward position (FIG. 19), although other springs or biasingmeans may be interconnected between the head restraint assembly 574 andthe seat back frame 530 for the same purpose.

Therefore, the head restraint assembly 574 is rotatable generally aboutthe axis of the interconnecting member 566 from a first configuration,or rearward position, of FIG. 19 to a second configuration, or forwardposition, of FIG. 20. When a seat occupant is properly positioned withinthe seat bottom and the seat back 522, the seat occupant's head may behorizontally positioned relative to the head restraint 524, and the seatoccupant's thorax may be horizontally positioned relative to the thoraxplate 560.

The head restraint control system 526 also includes a latch 600, and alock mechanism resetting device 602. The latch 600 includes a latch arm610 that extends from the horizontal member 540 and includes a latchingsurface portion 612, as discussed in greater detail below. Asschematically illustrated, the latch arm 610 is rotatably supported bythe horizontal member 540 at a latch attachment portion 616. A latch armstop 618 is attached to the horizontal member 540 for restricting therotation of the latch arm 610.

In the embodiment illustrated, the interconnecting member 566 willpermit the head restraint assembly 574 to rotate about the axis A-A asthe first plate member 562 rotates away from the latch arm 610. Asdiscussed in greater detail below, the latch arm 610 will rotate so asto interfere with the first plate member 562 and to restrain the headrestraint assembly 574 in the forward position (FIG. 20).

The lock mechanism resetting device 602 includes the guide pin 590, thegraphite washer 592, the first plate member spring 596, a latch lever620, and a latching rod 622. The latch lever 620 is rigidly attached tothe latch arm 610 so as to rotate with the latch arm 610 about the latchattachment portion 616. The latching rod 622 interconnects the latchlever 620 with the actuating member 582 to maintain a predetermineddistance between a portion of the latch lever 620 with a portion of theactuating member 582.

In operation, and assuming an event such as a rear-end collision thatwould accelerate the seat back 522 forward relative to a seat occupant,the kinetic energy generated by the reactive force between therelatively stationary seat occupant and the seat back 522 movinggenerally in the direction F, will result in a force on the thorax plate560 generally in the direction of arrow R. This force on the thoraxplate 560 will move the thorax plate 560 generally in the direction ofarrow R as the head restraint assembly 574 rotates about the axis A-A tomove the head restraint 524 generally in the forward direction (in thedirection of arrow F, from the rearward position of FIG. 20 to theforward position of FIG. 19) to permit the head restraint 524 to movetoward the seat occupant's head.

As the thorax plate 560 moves generally in the direction of arrow R, thethorax plate 560 (and the actuating member 582) will rotate about theaxis G, causing the actuating member 582 to move toward the first platemember 562. As the actuating member 582 moves toward the first platemember 562, the guide pin 590 is forced farther into the first platemember 562 (generally in the direction of the arrow U) and the latchingrod 622 is forced upward, generally in the direction of the arrow U. Asthe guide pin 590 is forced further into the first plate member 562, theplate member spring 596 resists the movement of the guide pin 592 andurges the guide pin 592 to move relative to the first plate member 562generally in the direction of the arrow D. As the latching rod 622 isforced upward, generally in the direction of the arrow U, the latch arm610 is rotated relative to the latch attachment portion 616 since thelatch lever 620 will urge the latch arm to rotate.

Since the head restraint assembly 574 has rotated to the forwardposition of FIG. 20, the latch arm 610 may then rotate toward theposition as shown in FIG. 20 until the latch arm 610 contacts the latcharm stop 618. In this position, the latching surface portion 612 willinterfere with the first plate member 562 so as to retain the firstplate member 562 in the forward position. Thus actuated in the forwardposition, the head restraint assembly 574 will not rotate toward therearward position of FIG. 19 until the latch arm 610 rotates toward theposition of FIG. 19.

With the restraint assembly 574 rotated to the forward position of FIG.20, and the guide pin 590 forced further into the first plate member562, the latch arm 610 may then be rotated as follows. Initially, thefirst plate member spring 596 will biasingly urge the guide pin 590 toretract from the first plate member 562. This action by the first platemember spring 596 will be counter acted by the frictional forces betweenthe graphite washer 592 and the guide pin 590 and/or the first platemember 562. In the embodiment illustrated, the guide pin 590 willretract from the first plate member 562 from the position of about FIG.20 to the position of about FIG. 19 in a few seconds (generally about 3seconds).

As the guide pin 590 retracts from the first plate member 562, thethorax plate 560 is rotated relative to the axis G and the latching rod622 is urged downward generally in the direction of the arrow D. Aslatching rod 622 is urged downward generally in the direction of thearrow D, the latch arm 610 is rotated about the latch attachment portion616 so as to permit the head restraint assembly 574 to rotate toward therearward position of FIG. 19. Once the head restraint assembly 574 isreturned to the rearward position of FIG. 19, the system 520 is reset soas to permit the system 520 to actuate again as described herein.

While embodiments of head restraint control systems, such as the headrestraint control systems 26, 126, 326, 526 and lock mechanisms, such asthe lock mechanisms 70, 170, 370, 570, are presented herein in selectedconfigurations, it would be understood that any lock mechanism and/orlock mechanism resetting device may be used with any head restraintcontrol system embodiment as detailed herein.

Non-electrical describes to a device that does not rely on electricityfor operation, such as the restraint systems 20, 120, 520 and the lockmechanism resetting device 202. More precisely, a non-electrical (ornon-chemical) device, such as are setting device for a lock mechanismwould not rely on any electrical controls or outside forces other thanthe actuation energy to reset a lock mechanism.

In the embodiments illustrated, the systems 20, 120, 520 do not includea source of energy for actuation. That is, there is no source of energysuch as a compressed spring or electrical source that is used to actuatethe head restraint system 20 and cause the moveable head restraint 24 totravel forward. A mechanical conversion of energy includes convertingenergy from rotational motion to linear motion and vice versa,converting fluid pressure into motion, and vice versa, and storingenergy in a spring or other biasing means. A mechanical conversion ofenergy does not include the flow of electricity, or chemical orpyrotechnical energy. An electrical or chemical conversion of energyincludes transmitting electrons to effect a flow of electricity.

For purposes of this application, it should be understood that anypotential energy stored in the headrest assembly components is ignoredas a source of energy that provides motion for the head restraint 24,and the kinetic energy provided by the relative movement between thethorax of a seat occupant and the thorax plate is the source of energyfor actuation of the system 20. As illustrated, this kinetic energy mustovercome any torsional energy required to deform the interconnectingmember 66, 166, 366 if any.

The preceding description has been presented only to illustrate anddescribe exemplary embodiments of the methods and systems of the presentinvention. It is not intended to be exhaustive or to limit the inventionto any precise form disclosed. It will be understood by those skilled inthe art that various changes may be made and equivalents may besubstituted for elements thereof without departing from the scope of theinvention. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the inventionwithout departing from the essential scope. Therefore, it is intendedthat the invention not be limited to the particular embodiment disclosedas the best mode contemplated for carrying out this invention, but thatthe invention will include all embodiments falling within the scope ofthe claims. The invention may be practiced otherwise than isspecifically explained and illustrated without departing from its spiritor scope. The scope of the invention is limited solely by the followingclaims.

1-15. (canceled)
 16. An apparatus comprising: a seat back having anouter surface that selectively contacts a seat occupant; a headrestraint extending from the seat back and having a head restraintportion that selectively contacts the seat occupant, wherein the headrestraint portion is moveable between a forward position and a rearwardposition; and a head restraint control assembly including: a lockmechanism for selectively restraining the headrest portion from movingfrom the forward position to the rearward position; and a lock mechanismresetting device operably coupled to at least a portion of the lockmechanism, wherein the head restraint portion will selectively movetoward the occupant relative to the seat back when the occupant exerts aforce on a portion of the head restraint control assembly, and whereinthe lock mechanism resetting device will reset the lock mechanism aftera time of about 300 milliseconds (ms) by converting at least a portionof the kinetic energy generated in the first actuation event into aresetting energy.
 17. The apparatus of claim 16, further comprising anactuator, wherein the actuator transfers an actuation force to the headrestraint portion for initiating movement of the head restraint portionfrom the rearward position to the forward position.
 18. The apparatus ofclaim 17, wherein the actuator does not include a source of energy foractuation other than the kinetic energy developed due to a resistiveforce between the seat occupant and the seat back.
 19. The apparatus ofclaim 16, wherein the lock mechanism will restrain the headrest portionfrom moving from the forward position to the rearward position in afirst actuation event and selectively reset by action of the lockmechanism resetting device in order to restrain the headrest portionfrom moving from the forward position to the rearward position in asecond actuation event.
 20. The apparatus of claim 19, wherein the lockmechanism resetting device includes a spring for at least temporarilystoring at least a portion of the resetting energy.